Science News

Patients With Early Parkinson's Exhibit Sleepiness, Hallucinations

Factors such as gender, age and overall health may help predict which people with early Parkinson's disease will experience hallucinations, sleepiness or swelling, a new study says.

These symptoms are reported more frequently by people with early Parkinson's disease than the general population, the study authors said.

"By identifying risk factors, it may help guide treatment decisions, allow for early intervention and possibly reduce disability," study author Dr. Kevin Biglan, a physician at the University of Rochester (N.Y.) School of Medicine, said in a prepared statement.

Biglan and his team analyzed data from a four-year clinical trial involving 301 people who had early Parkinson's disease. None of the participants reported hallucinations at the beginning of the study.

One out of five people in the study developed hallucinations. More than one out of three developed sleepiness, and almost one out of two developed swelling within four years of starting treatment with either levodopa or pramipexole.

"In contrast to other studies, we found being male, having multiple health problems and taking pramipexole were independently associated with developing sleepiness," Biglan said in the prepared statement. "This is the first time a patient's other health problems have been identified as a risk factor for drowsiness."

Writing in the July issue of Neurology, the researchers noted that being older, having multiple health problems and the presence of slight memory problems were associated with an increased risk of hallucinations.

The medications did not affect the risk of hallucinations.
Being female, having heart disease and pramipexole treatment were associated with an increased risk of swelling, the researchers said.

Parkinson's disease (PD) patients who receive medication treatment can expect improvements in their tremor, slowness and stiffness, but they may develop drug-related side effects during treatment. Having full knowledge of the relative risk of different side effects from different medications allows the neurologist and patient to decide together on a treatment plan and to share in the partnership of best medical management. In a recent Neurology article, Biglan and colleagues, from the University of Rochester (New York), studied three key side effects, somnolence (sleepiness), edema (ankle and leg swelling), and hallucinations (false images or sounds). The patients were part of a large study of early PD treatment and received either carbidopa/levodopa (Sinemet) or pramipexole (Mirapex) as their initial treatment. Later in the four-year study, additional carbidopa/levodopa could be added to control signs of parkinsonism. Over four years, somnolence developed or worsed in 35% of patients, edema developed or worsed in 45%, and hallucinations developed in 17%. Initial treatment with pramipexole, men and the co-existence of multiple (greater than five) medical problems in addition to PD increased the risk of somnolence. Initial treatment with pramipexole, women, and concomitant heart disease increased the risk for edema. Old age, higher cognitive function at study entry, and multiple co-existant medical problems increased the risk for hallucinations. Unlike the other two side effects, the development of hallucinations was not more linked to one drug treatment than to the other.

The choice of early drug treatment for PD has received considerable attention in the past, and prior studies that focused on the risk of dyskinesias (involuntary jerking movements) strongly favored dopamine agonists like pramipexole over carbidopa/levodopa. This new study balances those earlier reports and shows that side effect profiles differ among the available drugs to treat PD and that neither pramipexole or carbidopa/levodopa can be considered unconditionally better than the other in terms of side effects. Well-informed patients and their physicians need to consider the relative risks of different treatments and their concerns about specific side effects when developing a treatment plan. Importantly, patients must understand that these analyses examined a large population of patients, and most patients did not develop the three side effects. The documented increased risk of somnolence and edema with pramipexole does not mean that any specific patient will necessarily develop the side effect, but the results emphasize that the likelihoods of somnolence and edema are increased with pramipexole, especially if the other associated risk factors (gender and medical illnesses specified above) occur as well. Before starting treatment for PD, patients will want to read about dyskinesias, somnolence, and edema, and speak with their physician about their concerns regarding the impact that these side effects might have on their life. Those with greatest concerns about dyskinesias will likely select a dopamine agonist (pramipexole for example). Those most concerned about somnolence or edema will likely favor carbidopa/levodopa. Of course, other issues including cost differences, additional side effect concerns, as well as personal experience and preferences, will contribute to the final best decision.